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Bryant Plus 90 398AAZ Not Firing

Went to use the furnace for the first time this fall last night. Turned on the thermostat and heard the inducer motor spin up. I walked away but then noticed 5 mins later that the furnace wasn't running. Checked to make sure the thermostat was calling for heat. Went downstairs, flipped of the power, turned it back on and the inducer motor spun up again. But, after 20-25 seconds it shut off with no pilot start. I tried this a few times, on/off with the power switch, and it finally took. It worked all of last night. This morning, no heat again. No matter what I tried I can't get it to fire anymore. The inducer motor will run for 20-25 seconds and then just shuts off.

If you system is intermittent see if you can "read the code" through the window on the front door of the furnace. Most will have an LED that blinks a code. Could be handy info for the tech to troubleshoot your system, especially if it just happens to work when the tech gets there.

If you system is intermittent see if you can "read the code" through the window on the front door of the furnace. Most will have an LED that blinks a code. Could be handy info for the tech to troubleshoot your system, especially if it just happens to work when the tech gets there.

Unfortunately, this unit is from around 1990, before they had the newer intelligent systems that would display error codes.